Thanks. I haven't worked through the code, but it appears the
at(mean) option avoids the buggy part of the code that Kit
discovered. Unfortunately, using at(mean) wipes out one of the
biggest advantages of margeff, which is getting the average partial
effects. The new margins command will now get you the average
partial effects, but margeff is often quicker and easier (plus it is
just about the only option if you don't have Stata 11).